We get asked time and time again whether octane boosters work. The answer is yes and no because it really depends on the application and what you are trying to achieve. Let us clarify.
Firstly, we need to understand why octane boosters exist in the first place – it is to prevent the onset of detonation. Detonation is described as: “Excessively rapid burning of the fuel mixture, often caused by auto-ignition due to excessive temperatures in the combustion chamber, incorrect ignition timing, lean mixtures, too high a compression ratio or unsuitable fuel.” Basically, a too-low an octane rating of the given fuel. Heard as a faint, metallic rattle, detonation is accompanied by a loss of power and can cause serious damage to piston crowns. It is also known as pinking.
The significance of detonation is such that many companies produce fuel additives designed to increase the inherent octane rating of a given fuel. The proliferation of octane boosters has in part come about in recent times thanks to low quality fuels, particularly with the demise of leaded fuel, which had a much higher octane rating.
This presents a problem for high-performance cars designed to run on higher octane or 100 RON Japanese fuel. Japanese import performance cars, Subaru’s STI WRX for example, run an ECU program for 98 to 100 octane fuel and may detonate on lower octane fuels if the ECU is unable to compensate for the lower octane. Some have even had ECU upgrades that require 102 Ron fuel but this is readily available in Japan but not in Europe or the US, or certainly not from a conventional gas station.
Normally, octane boosters would be of little use if an engine is not detonating. However, with the advent of more sophisticated ECU/EFI programming many engines can optimise the engine management system by advancing the ignition timing and thus benefit from higher octane fuel. This means more power. They are also advantageous as an “octane buffer” for highly tuned vehicles. For example, if your vehicle’s fuelling and ignition is mapped for 98 octane and you are using 98 octane fuels, then it may be of benefit to use an octane booster to increase the octane to 99 or 100 as a safety margin, in the event of having “degraded” fuel etc.
Honda’s S2000 2.0-litre engine for example, running a high 11.0:1 compression ratio, relies on advanced engine management as much as quality fuel. But it can sustain its power on a lower octane pump fuel because the ECU compensates. However this is achieved by reducing the ignition timing and thus results in degradation in performance. This is where a modern vehicle with advanced engine management can take advantage of a higher octane fuel or a base pump fuel plus an octane booster.
Also, any turbo owner who has experimented with boost will know if you run too much, it will detonate, so improving the octane is vital for maximum performance. However, non-performance vehicles designed and mapped to run comfortably on base pump fuel, say 95 RON, will not gain a performance advantage. Sure, many octane boosters offer other advantages such as valve protection etc, but it will not gain in power. Unless…..the vehicle in question has been remapped or chipped, or tuned in such a way that it can take advantage of a higher octane fuel.
For example: if you take a bog standard Ford Fiesta that is designed to run of pump fuel then there will be no performance increase from using an octane booster. But if you have the ECU (fuel and ignition) remapped for a higher octane then it will be necessary to use either a higher octane fuel or a base fuel plus and octane booster in order to achieve the power safely. Octane boosters are popular in the performance scene because they often regain power lost through detonation as a result of tuning upgrades.
Unfortunately, some popular TV car shows have been quick to rubbish the use of octane boosters. One for example demonstrated the use of several products on low performance cars such with basic engine management such as a Peugeot 106, basic Clio etc. We could have told you the results before they even started. They were all vehicles designed to run on basic low octane pump fuel and their ECUs are not sophisticated enough to take advantage of a higher octane fuel let alone an octane booster. Of course, it doesn’t help when many manufactures put ridiculous claims on their labels implying that octane boosters will increase performance on all vehicles when clearly they won’t.
You can/should use an octane booster if:
You have a modern medium to high performance vehicle and wish to make the most of the available power, and you are unable to easily obtain a good quality high octane fuel in your given area.
Your vehicle manual specifies a particular high octane fuel (i.e. 98 Ron super unleaded) but you are only able to find 97 Ron or below. To clarify, many modern cars will adapt accordingly if using a lower octane fuel than that specified but a reduction in performance will result.
You suspect that you may have a tank of old or bad fuel where the octane value has deteriorated.
Your engine has been mapped specifically for a higher octane fuel and/or the engine has been mapped very closely to the edge (detonation threshold) and you require an increase in octane to provide a buffer.
You have modified you vehicle in other ways such as an increase in the turbo boost pressure making detonation much more likely.
You are about to go on a track day where the engine will spend most of its time under considerable stress and you wish to prevent the onset of detonation under prolonged high-stress conditions.
You are not looking for a performance increase but wish to lubricate and protect the valves but using an octane booster in small regular dosages.
We hope this helps clarify any confusion. If you want to establish the best performing octane boosters then click here see the Octane Booster test results.
The FuelTechExperts Team